Electromagnetic relay

Abstract

To facilitate adjustment of an engagement condition including rigidity of an engaging part for preventing a cover from being blown off when an arc occurs in an electromagnetic relay.SOLUTION: An electromagnetic relay comprises a contact part, a case, and a cover. The contact part includes a fixed contact and a movable contact. The case includes an internal space, a side wall, a first main opening, a first engaged part, and a second engaged part. The contact part is disposed in the internal space. The side wall surrounds the internal space. The first main opening allows communication between the internal space and the outside. The cover includes a cover body, a first engaging part, and a second engaging part. The first engaging part is connected to the cover body. The second engaging part is connected to the cover body at a position different from that of the first engaging part. The cover is held in either a normal position or a pressure-releasing position. In the normal position, the first engaging part engages with the first engaged part, and the cover body closes the first main opening. In the pressure-releasing position, the second engaging part engages with the second engaged part, and the cover body opens the first main opening.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to an electromagnetic relay. [Background technology]

[0002] In an electromagnetic relay, an arc may occur when a large current flows through the contacts and the contacts separate. The energy of this arc increases the internal pressure of the case of the electromagnetic relay. For example, Patent Document 1 discloses an electromagnetic relay equipped with a structure for preventing the case cover from being blown off due to an increase in internal pressure. In this electromagnetic relay, the cover includes a cover body and an engagement leg portion. The engagement leg portion extends from the cover body. The engagement leg portion is provided with a first engagement hook and a second engagement hook. The first engagement hook and the second engagement hook are arranged vertically side by side on the engagement leg portion, and the second engagement hook is arranged below the first engagement hook. The case is provided with a hook engagement portion with which the first engagement hook and the second engagement hook engage.

[0003] In the above-described electromagnetic relay, in a normal state where no arc is generated, the first engagement hook engages with the hook engagement portion, thereby attaching the cover to the case. When the internal pressure of the case increases due to an arc, the engagement leg elastically deforms, causing the first engagement hook to disengage from the hook engagement portion. This causes the cover to lift off the case, forming a gap between the cover and the case. Air inside the case is released through this gap to the outside, reducing the internal pressure of the case. Furthermore, as the cover rises, the second engagement hook engages with the hook engagement portion, preventing the cover from being blown off. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-114450 Summary of the Invention [Problem to be solved by the invention]

[0005] In the electromagnetic relay described above, the first engagement hook is required to have a rigidity sufficient to disengage easily with a low load so that it disengages from the hook engagement portion when the internal pressure increases. Meanwhile, the second engagement hook is required to have a rigidity sufficient to withstand a high load so that it does not disengage from the hook engagement portion when the internal pressure increases. However, in the above electromagnetic relay, the first engagement hook and the second engagement hook are provided on the same engagement leg. Therefore, it is difficult to adjust the rigidity of the first engagement hook and the second engagement hook as described above when designing the electromagnetic relay. An object of the present invention is to facilitate adjustment of the engagement level, including the rigidity of the engagement portion, in an electromagnetic relay to prevent the cover from being blown off when an arc occurs. [Means for solving the problem]

[0006] An electromagnetic relay according to one aspect of the present invention includes a contact portion, a case, and a cover. The contact portion includes a fixed contact and a movable contact. The case includes an internal space, a side wall, a first main opening, a first engaged portion, and a second engaged portion. The contact portion is disposed in the internal space. The side wall surrounds the internal space. The first main opening connects the internal space to the outside. The cover is attached to the case. The cover includes a cover body, a first engaging portion, and a second engaging portion. The first engaging portion is connected to the cover body. The second engaging portion is connected to the cover body at a position different from the first engaging portion. The cover is held in either a normal position or a pressure release position. In the normal position, the first engaging portion engages with the first engaged portion, and the cover body closes the first main opening. In the pressure release position, the second engaging portion engages with the second engaged portion, and the cover body opens the first main opening.

[0007] In the electromagnetic relay according to this aspect, when no arc is occurring, the cover is held in the normal position. When the cover is in the normal position, the first engaging portion engages with the first engaged portion, and the cover body closes the first main opening. When the internal pressure of the case increases due to an arc, the internal pressure disengages the first engaging portion from the first engaged portion, causing the cover to lift off the case. Then, the second engaging portion engages with the second engaged portion, holding the cover in the pressure release position. This prevents the cover from being blown off. Furthermore, when the cover is in the pressure release position, the cover body opens the first main opening. This allows air inside the case to be released to the outside, reducing the internal pressure inside the case. Furthermore, in the electromagnetic relay according to this aspect, the second engaging portion is connected to the cover body at a position different from that of the first engaging portion. This makes it easy to adjust the engagement between the first engaging portion and the second engaging portion, including their rigidity. [Effects of the Invention]

[0008] According to the present invention, in an electromagnetic relay, it is possible to easily adjust the degree of engagement, including the rigidity of the engagement portion, for preventing the cover from being blown off when an arc occurs. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of an electromagnetic relay according to an embodiment. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] 6 is a cross-sectional view of the electromagnetic relay taken along line VI-VI in FIG. 2. [Figure 7] FIG. 2 is a perspective view of the electromagnetic relay with the upper case omitted. [Figure 8] 8 is a top view of the electromagnetic relay shown in FIG. 7 from which a drive unit and an inner board are omitted. [Figure 9] 8 is a top view of the electromagnetic relay shown in FIG. 7 from which a drive unit and an inner board are omitted. [Figure 10] FIG. [Figure 11] FIG. 2 is a perspective view of the electromagnetic relay with the cover in the pressure release position. [Figure 12] 10 is a cross-sectional view showing a first engaging portion and a first engaged portion when the cover is in a normal position. FIG. [Figure 13] 10 is a cross-sectional view showing a second engaging portion and a second engaged portion when the cover is in a normal position. FIG. [Figure 14] 10 is a cross-sectional view showing a second engaging portion and a second engaged portion when the cover is in a pressure release position. FIG. [Figure 15] FIG. 10 is a perspective view showing a cover of an electromagnetic relay according to a first modified example. [Figure 16] FIG. 10 is a front view showing an electromagnetic relay according to a second modified example. [Figure 17] FIG. 10 is a perspective view showing an electromagnetic relay according to a third modified example. [Figure 18] FIG. 10 is a perspective view showing an electromagnetic relay according to a fourth modified example. [Figure 19] FIG. 10 is a perspective view showing an electromagnetic relay according to a fifth modified example. [Figure 20] FIG. 10 is a perspective view showing an electromagnetic relay according to a sixth modified example. [Figure 21] FIG. 13 is a perspective view showing an electromagnetic relay according to a seventh modified example. [Figure 22] FIG. 13 is a perspective view showing an electromagnetic relay according to an eighth modified example. [Figure 23] FIG. 13 is a perspective view showing an electromagnetic relay according to a ninth modified example. [Figure 24] FIG. 13 is a perspective view showing an electromagnetic relay according to a ninth modified example. [Figure 25] FIG. 23 is a side view showing an electromagnetic relay according to a tenth modified example. [Figure 26] FIG. 23 is a cross-sectional view of the cover and case of an electromagnetic relay according to an eleventh modification. [Figure 27] FIG. 23 is a perspective view showing an electromagnetic relay according to a twelfth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an electromagnetic relay according to an embodiment will be described with reference to the drawings. FIG. 1 is a perspective view of an electromagnetic relay 1 according to an embodiment. FIG. 2 is a front view of the electromagnetic relay 1. FIG. 3 is a side view of the electromagnetic relay 1. FIG. 4 is a perspective view of the electromagnetic relay 1. FIG. 5 is an exploded perspective view of the electromagnetic relay 1. FIG. 6 is a cross-sectional view of the electromagnetic relay 1 taken along line VI-VI in FIG. 2. As shown in FIGS. 1 to 6, the electromagnetic relay 1 includes a case 2, a cover 3, a drive unit 4, a moving member 5, and a contact unit 6.

[0011] The cover 3 is separate from the case 2. The cover 3 is attached to the case 2. The cover 3 is made of resin. The cover 3 has a substantially rectangular shape. In the following description, the direction in which the long sides of the cover 3 extend is defined as the front-rear direction. The direction in which the short sides of the cover 3 extend is defined as the left-right direction.

[0012] As shown in FIG. 6, the case 2 includes an internal space S1. The drive unit 4, the moving member 5, and the contact unit 6 are arranged within the internal space S1 of the case 2. The case 2 includes an upper case 7, a lower case 8, and an inner board 9. The upper case 7, the inner board 9, and the lower case 8 are separate from one another. The upper case 7 is made of resin. The upper case 7 is attached to the inner board 9. The upper case 7 is attached to the inner board 9 by, for example, a snap fit.

[0013] More specifically, as shown in FIG. 5 , the upper case 7 has a generally rectangular parallelepiped shape with openings at the top and bottom. The upper case 7 includes a first internal space S2, a side wall 11, a first main opening 12, and a second main opening 13. The side wall 11 surrounds the first internal space S2. The side wall 11 includes a front surface 14, a rear surface 15, a left side surface 16, and a right side surface 17. The length of the front surface 14 and the rear surface 15 in the left-right direction is shorter than the length of the left side surface 16 and the right side surface 17 in the front-to-rear direction. The first main opening 12 is provided on the top surface of the upper case 7. The second main opening 13 is provided on the bottom surface of the upper case 7. The first main opening 12 and the second main opening 13 communicate the first internal space S2 with the outside of the upper case 7.

[0014] A pair of left mounting holes 18A, 18B are provided on the left side surface 16 of the upper case 7. The inner board 9 includes a pair of left mounting claws 19A, 19B. The pair of left mounting claws 19A, 19B engage with the pair of left mounting holes 18A, 18B, respectively, thereby attaching the upper case 7 to the inner board 9. Although not shown, a pair of right mounting holes are provided on the right side surface 17 of the upper case 7, and the pair of right mounting claws of the inner board 9 engage with the pair of right mounting holes, respectively.

[0015] The lower case 8 is disposed below the upper case 7. The lower case 8 is made of an insulating material such as resin. The inner board 9 is disposed on the lower case 8. The inner board is attached to the lower case 8. The inner board 9 is disposed between the upper case 7 and the lower case 8. The inner board 9 is made of an insulating material such as resin. As shown in FIG. 6, the lower case 8 and the inner board 9 together form a second internal space S3. The lower case 8 covers the second internal space S3 from below. The inner board 9 covers the second internal space S3 from above. The inner board 9 includes a partition wall 20. The partition wall 20 separates the first internal space S2 from the second internal space S3.

[0016] As shown in Fig. 6, the drive unit 4 is disposed in the first internal space S2 of the upper case 7. Fig. 7 is a perspective view of the electromagnetic relay 1 with the upper case 7 omitted. As shown in Figs. 6 and 7, the drive unit 4 includes a coil 21, a spool 22, an iron core 23, a yoke 24, a hinge spring 25, and an armature 26. The coil 21 is wound around the spool 22. Coil terminals 27A and 27B are connected to the coil 21. As shown in Fig. 5, the coil terminals 27A and 27B are supported by the lower case 8 and the inner board 9.

[0017] The iron core 23 is disposed within the spool 22. The iron core 23 extends in the front-to-rear direction. The yoke 24 has an L-shaped bent shape. The yoke 24 is disposed in front of and above the spool 22. The yoke 24 is connected to the iron core 23. The hinge spring 25 is connected to the yoke 24 and the armature 26. The armature 26 is supported so as to be rotatable around the upper end of the armature 26. As the armature 26 rotates around the upper end, the lower end of the armature 26 moves back and forth. The armature 26 is disposed behind the iron core 23. The hinge spring 25 biases the armature 26 in a direction away from the iron core 23. In other words, the hinge spring 25 biases the armature 26 rearward.

[0018] The moving member 5 is made of an insulating material such as resin. FIG. 8 is a top view of the electromagnetic relay 1 shown in FIG. 7 with the drive unit 4 and inner board 9 omitted. As shown in FIGS. 6 and 8, the moving member 5 extends in the front-to-rear direction. The moving member 5 is supported by the lower case 8 so as to be movable in the front-to-rear direction. The moving member 5 includes a receiving portion 28. The receiving portion 28 has a shape recessed from the upper surface of the moving member 5. The lower end of the armature 26 is disposed within the receiving portion 28. The moving member 5 moves back and forth when pressed by the lower end of the armature 26.

[0019] The contact portion 6 is disposed within the second internal space S3 of the lower case 8 and the inner board 9. A partition wall 20 separates the contact portion 6 from the first internal space S2. The contact portion 6 includes fixed contacts 29A-29H, fixed terminals 30A-30H, movable contacts 31A-31H, and movable contact pieces 32A-32H. The fixed terminals 30A-30H extend in the vertical direction. The lower ends of the fixed terminals 30A-30H protrude downward from the lower case 8.

[0020] The fixed contacts 29A-29H are connected to the fixed terminals 30A-30H, respectively. The movable contacts 31A-31H are arranged opposite the fixed contacts 29A-29H, respectively. The movable contacts 31A-31H are connected to the movable contact pieces 32A-32H, respectively. The movable contact pieces 32A-32H are supported by the movable member 5.

[0021] The movable contact pieces 32A-32H move in the front-rear direction together with the moving member 5. When the movable contact pieces 32A-32H move in the contact direction, the movable contacts 31A-31H come into contact with the fixed contacts 29A-29H. When the movable contact pieces 32A-32H move in the separation direction, the movable contacts 31A-31H separate from the fixed contacts 29A-29H. In this embodiment, the contact direction is forward, and the separation direction is rearward. However, the contact direction and the separation direction are not limited to these directions, and may be different directions. A return spring 33 is attached to the moving member 5. The return spring 33 biases the movable contact pieces 32A-32H in the separation direction.

[0022] 6, contact springs 34A-34D are arranged between the movable contact pieces 32A-32D and the moving member 5. The contact springs 34A-34D urge the movable contact pieces 32A-32D in the contact direction, respectively. Although not shown, contact springs similar to the contact springs 34A-34D are also arranged between the movable contact pieces 32E-32H and the moving member 5.

[0023] Next, we will explain the operation of the electromagnetic relay 1. When the coil 21 is not energized, the movable member 5 is pressed in the opening direction by the biasing forces of the hinge spring 25 and the return spring 33, and the movable member 5 is located in the opening position shown in Fig. 8. In this state, the movable contacts 31A-31H are open from the fixed contacts 29A-29H.

[0024] When coil 21 is energized, armature 26 is attracted to iron core 23 and rotated by the magnetic force of coil 21, and moving member 5 is pressed in the contact direction by armature 26. As a result, moving member 5 moves to the contact position shown in Fig. 9 against the biasing forces of return spring 33 and hinge spring 25. Movable contact pieces 32A-32H also move in the contact direction together with moving member 5, and movable contacts 31A-31H come into contact with fixed contacts 29A-29H.

[0025] When the current supply to coil 21 is stopped, moving member 5 moves in the opening direction due to the biasing forces of hinge spring 25 and return spring 33. As a result, moving member 5 returns to the opening position shown in Fig. 8, and movable contacts 31A-31H are opened from fixed contacts 29A-29H.

[0026] Next, the pressure relief structure of the electromagnetic relay 1 will be described. The electromagnetic relay 1 has a pressure relief structure that releases internal pressure in the case 2 when an arc occurs at the contacts. In detail, as shown in FIGS. 1 to 5, the upper case 7 includes a plurality of first engaged portions 40, 41 and a plurality of second engaged portions 42-45. The first engaged portions 40, 41 are provided on the left side surface 16 and the right side surface 17, which are the long side surfaces of the upper case 7. The second engaged portions 42-45 are provided on the front surface 14 and the rear surface 15, which are the short side surfaces of the upper case 7. The second engaged portions 42-45 are arranged below the first engaged portions 40, 41.

[0027] The multiple first engaged portions 40, 41 are holes. The multiple first engaged portions 40, 41 include a first left engaged portion 40 and a first right engaged portion 41. The first left engaged portion 40 is provided on the left side surface 16 of the upper case 7. The first left engaged portion 40 is disposed in the center of the left side surface 16 in the front-to-rear direction. The left side surface 16 includes a left convex portion 46. The left convex portion 46 protrudes from the outer surface of the left side surface 16. The left convex portion 46 extends in the up-down direction on the left side surface 16. The first left engaged portion 40 is provided on the left convex portion 46.

[0028] The first right engaged portion 41 is provided on the right side surface 17 of the upper case 7. The first right engaged portion 41 is located in the center of the right side surface 17 in the front-to-rear direction. The right side surface 17 includes a right convex portion 47. The right convex portion 47 protrudes from the outer surface of the right side surface 17. The right convex portion 47 extends in the up-down direction on the right side surface 17. The first right engaged portion 41 is provided on the right convex portion 47.

[0029] The upper case 7 includes a plurality of sub-openings 48-51. The plurality of second engaged portions 42-45 are upper edges of the plurality of sub-openings 48-51, respectively. The plurality of second engaged portions 42-45 include a pair of second front engaged portions 42, 43 and a pair of second rear engaged portions 44, 45. The pair of second front engaged portions 42, 43 are provided on the front surface 14 of the upper case 7. The front surface 14 includes a front recess 52. The front recess 52 is recessed from the outer surface of the front surface 14. The front recess 52 extends in the up-down direction on the front surface 14. The pair of second front engaged portions 42, 43 are located on the left and right sides of the front recess 52, respectively. The rear surface 15 includes a rear recess 53. The rear recess 53 is recessed from the outer surface of the rear surface 15. The rear recess 53 extends in the up-down direction on the rear surface 15. The pair of second rear engaged portions 44, 45 are disposed on the left and right sides of the rear recessed portion 53, respectively.

[0030] The plurality of sub-openings 48-51 are provided in the side wall 11 of the upper case 7. The plurality of sub-openings 48-51 are arranged between the contact portion 6 and the first main opening 12. The plurality of sub-openings 48-51 extend in the up-down direction. The plurality of sub-openings 48-51 include a pair of front sub-openings 48, 49 and a pair of rear sub-openings 50, 51. The pair of second front engaged portions 42, 43 are upper edges of the pair of front sub-openings 48, 49, respectively. The pair of second rear engaged portions 44, 45 are upper edges of the pair of rear sub-openings 50, 51, respectively.

[0031] The pair of front sub-openings 48, 49 are provided on the front surface 14 of the upper case 7. The pair of front sub-openings 48, 49 are arranged on the front surface 14 on the left and right sides of the front recessed portion 52, respectively. The pair of rear sub-openings 50, 51 are provided on the rear surface 15 of the upper case 7. The pair of rear sub-openings 50, 51 are arranged on the rear surface 15 on the left and right sides of the rear recessed portion 53, respectively.

[0032] FIG. 10 is a perspective view of the cover 3. As shown in FIG. 10, the cover 3 includes a cover body 60, a plurality of first engagement portions 61, 62, and a plurality of second engagement portions 63-66. The cover body 60 has a rectangular plate shape. The cover body 60 covers the first main opening 12. For example, the cover body 60 has a shape that fits the first main opening 12. Alternatively, the cover body 60 may be larger than the first main opening 12. The plurality of first engagement portions 61, 62 are connected to the cover body 60. The plurality of second engagement portions 63-66 are connected to the cover body 60 at positions different from the positions of the plurality of first engagement portions 61, 62. The plurality of first engagement portions 61, 62 are connected to a left edge 67 and a right edge 68, which are edges on the long sides of the cover body 60. The plurality of second engagement portions 63-66 are connected to a front edge 69 and a rear edge 70, which are edges on the short sides of the cover body 60. The second engagement portions 63-66 are longer than the first engagement portions 61, 62 in the vertical direction.

[0033] In detail, the multiple first engagement portions 61, 62 include a first left engagement portion 61 and a first right engagement portion 62. The first left engagement portion 61 is connected to a left side edge 67 of the cover main body 60. The first left engagement portion 61 is connected to a central portion of the left side edge 67 in the front-to-rear direction. The first left engagement portion 61 includes a first left lever portion 61A and a first left hook portion 61B. The first left lever portion 61A extends downward from the cover main body 60. The inner surface of the first left lever portion 61A has a flat shape. The first left hook portion 61B protrudes from the outer surface of the first left lever portion 61A.

[0034] The first right engagement portion 62 is connected to a right edge 68 of the cover body 60. The first right engagement portion 62 is connected to a central portion of the right edge 68 in the front-to-rear direction. The first right engagement portion 62 includes a first right lever portion 62A and a first right hook portion 62B. The first right lever portion 62A extends downward from the cover body 60. The inner surface of the first right lever portion 62A has a flat shape. The first right hook portion 62B protrudes from the outer surface of the first right lever portion 62A.

[0035] The multiple second engagement portions 63-66 include a pair of second front engagement portions 63, 64 and a pair of second rear engagement portions 65, 66. The pair of second front engagement portions 63, 64 are connected to a front edge 69 of the cover main body 60. The pair of second front engagement portions 63, 64 are spaced apart on the left and right sides of the front edge 69. The second front engagement portion 63 includes a second front lever portion 63A and a second front hook portion 63B. The second front lever portion 63A extends downward from the cover main body 60. The inner surface of the second front lever portion 63A includes a front recessed groove 63C. The front recessed groove 63C extends in the up-down direction on the inner surface of the second front lever portion 63A. The second front lever portion 63A has a U-shaped cross section. This improves the rigidity of the second front lever portion 63A. The second front engagement portion 64 has a similar shape to the second front engagement portion 63 and includes a second front lever portion 64A, a second front hook portion 64B, and a front recessed groove 64C. The second front hook portions 63B, 64B are positioned lower than the first left hook portion 61B and the first right hook portion 62B. The second front hook portions 63B, 64B are disposed within the front sub-openings 48, 49, respectively.

[0036] The pair of second rear engagement portions 65, 66 are connected to a rear edge 70 of the cover main body 60. The pair of second rear engagement portions 65, 66 are spaced apart on the left and right sides of the rear edge 70. The second rear engagement portion 65 includes a second rear lever portion 65A and a second rear hook portion 65B. The second rear lever portion 65A extends downward from the cover main body 60. The inner surface of the second rear lever portion 65A includes a rear recessed groove 65C. The rear recessed groove 65C extends in the up-down direction on the inner surface of the second rear lever portion 65A. The second rear lever portion 65A has a U-shaped cross section. This improves the rigidity of the second rear lever portion 65A. The second rear engagement portion 66 also has a shape similar to the second rear engagement portion 65 and includes a second rear lever portion 66A and a second rear hook portion 66B. The second rear hook portions 65B, 66B are located lower than the first left hook portion 61B and the first right hook portion 62B. The second rear hook portions 65B, 66B are disposed within the rear sub-openings 50, 51, respectively.

[0037] The cover 3 is held in either a normal position shown in FIG. 1 or a pressure-release position shown in FIG. 11. As shown in FIGS. 1 and 12, when the cover 3 is in the normal position, the first engagement portions 61, 62 are engaged with the first engaged portions 40, 41, respectively. That is, when the cover 3 is in the normal position, the first left engagement portion 61 is engaged with the first left engaged portion 40, and the first right engagement portion 62 is engaged with the first right engaged portion 41. In the normal position, the cover 3 is attached to the case 2 by snap-fitting between the first engagement portions 61, 62 and the first engaged portions 40, 41. In this state, the cover body 60 closes the first main opening 12. As shown in FIGS. 1 and 13, the second front engagement portion 63 faces the front sub-opening 48 and closes it. The second rear engagement portion 65 faces the rear sub-opening 50 and closes it. Similar to the second front engagement portion 63, the second front engagement portion 64 also faces the front sub-opening 49 and closes the front sub-opening 49. Similar to the second rear engagement portion 65, the second rear engagement portion 66 also faces the rear sub-opening 51 and closes the rear sub-opening 51.

[0038] When an arc occurs at the contacts, the heat of the arc increases the internal pressure of the case 2. The increased internal pressure acts on the cover 3, causing it to lift up from the case 2. The increased internal pressure also acts on the case 2, causing it to expand. These forces elastically deform the cover 3 and the case 2, causing the multiple first engaging portions 61, 62 to disengage from the multiple first engaged portions 40, 41, respectively. As a result, the cover 3 moves upward relative to the case 2.

[0039] After the cover 3 rises, as shown in FIGS. 11 and 14 , the second engaging portions 63-66 engage with the second engaged portions 42-45, respectively. This stops the cover 3 from rising and keeps it in the pressure release position. That is, when the cover 3 is in the pressure release position, the pair of second front engaging portions 63, 64 engage with the pair of second front engaged portions 42, 43, respectively. Furthermore, the pair of second rear engaging portions 65, 66 engage with the pair of second rear engaged portions 44, 45, respectively. In this state, the cover body 60 opens the first main opening 12. Furthermore, the cover body 60 is positioned higher than the upper edge of the side wall 11 of the upper case 7, and a gap is provided between the cover body 60 and the upper edge of the side wall 11. Therefore, air in the internal space S1 of the case 2 is discharged to the outside of the case 2 through the first main opening 12 and the gap. This reduces the internal pressure in the case 2 and prevents the cover 3 from being blown off. The cover 3 can be returned from the pressure release position to the normal position by being pushed downward toward the case 2.

[0040] When the cover 3 moves from the normal position to the pressure release position, the second front engagement portions 63, 64 move along the front sub-openings 48, 49. As a result, the second front engagement portions 63, 64 open the front sub-openings 48, 49. Furthermore, the second rear engagement portions 65, 66 move along the rear sub-openings 50, 51. As a result, the second rear engagement portions 65, 66 open the rear sub-openings 50, 51. The front sub-openings 48, 49 and the rear sub-openings 50, 51 are disposed between the contact portion 6 and the first main opening 12. Therefore, air in the internal space S1 is released from the front sub-openings 48, 49 and the rear sub-openings 50, 51, thereby reducing the pressure acting on the cover 3. This reduces the stress on the second engagement portions 63-66 and prevents damage to the second engagement portions 63-66.

[0041] Furthermore, the contact portion 6 and the first main opening 12 are separated by a partition wall 20. Therefore, even when the first main opening 12 is open, arcs from the contact portion 6 or molten metals caused by the arc are unlikely to leak out of the case 2.

[0042] In the electromagnetic relay 1 according to the present embodiment described above, the pressure relief structure described above prevents the cover 3 from being blown off. Furthermore, in the electromagnetic relay 1, the second engaging portions 63-66 are connected to the cover body 60 at positions different from the first engaging portions 61, 62. The second engaged portions 42-45 are provided at positions different from the first engaged portions 40, 41. Therefore, it is easy to adjust the degree of engagement, including the rigidity between the first engaging portions 61, 62 and the second engaging portions 63-66, and the rigidity between the first engaged portions 40, 41 and the second engaged portions 42-45, at the time of design.

[0043] For example, by differentiating the portions of the cover body 60 to which the first engagement portions 61, 62 are connected from the portions to which the second engagement portions 63-66 are connected, it is possible to adjust the strength of engagement between the first engagement portions 61, 62 and the second engagement portions 63-66. That is, in the above embodiment, the first engagement portions 61, 62 are connected to the left edge 67 and the right edge 68 of the long side, which has lower rigidity. This weakens the engagement. The second engagement portions 63-66 are connected to the front edge 69 and the rear edge 70 of the short side, which has higher rigidity. This strengthens the engagement. In addition, by differentiating the cross-sectional shapes of the first engagement portions 61, 62 and the second engagement portions 63-66, it is possible to adjust the rigidity between the first engagement portions 61, 62 and the second engagement portions 63-66.

[0044] The rigidity of the first engaged portions 40, 41 and the second engaged portions 42-45 can be adjusted by providing different portions of the side wall 11 of the case 2 on different sides. In other words, in the above embodiment, the first engaged portions 40, 41 are provided on the left side surface 16 and the right side surface 17 of the long sides, thereby reducing their rigidity. The second engaged portions 42-45 are provided on the front surface 14 and the rear surface 15 of the short sides, thereby increasing their rigidity. This makes it easier for the first engaging portions 61, 62 to disengage from the first engaged portions 40, 41. Meanwhile, the second engaging portions 63-66 are less likely to disengage from the second engaged portions 42-45.

[0045] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the gist of the invention.

[0046] The configuration of the electromagnetic relay 1 is not limited to that of the above embodiment and may be modified. The configuration of the contact unit 6 is not limited to that of the above embodiment and may be modified. For example, the number of movable contacts and the number of fixed contacts are not limited to that of the above embodiment and may be modified.

[0047] The configuration of the drive unit 4 is not limited to that of the above embodiment and may be modified. For example, the drive unit 4 may be a so-called plunger type. The coil 21, coil terminals 27A and 27B, and yoke 24 may be partially or entirely covered with a resin mold. In this case, dielectric breakdown of the drive unit 4 due to molten metal or the like from the contact portion 6 is suppressed.

[0048] The configurations of the case 2 and the cover 3 are not limited to those of the above embodiment and may be modified. For example, the shapes of the first engaged portions 40, 41, the second engaged portions 42-45, the first engaging portions 61, 62, or the second engaging portions 63-66 are not limited to those of the above embodiment and may be modified. In the above embodiment, the first engaged portions 40, 41 are holes, and the first engaging portions 61, 62 are hook-shaped. However, conversely, the first engaged portions 40, 41 may be hook-shaped, and the first engaging portions 61, 62 may be holes. In the above embodiment, the second engaged portions 42-45 are holes, and the second engaging portions 63-66 are hook-shaped. However, conversely, the second engaged portions 42-45 may be hook-shaped, and the second engaging portions 63-66 may be holes.

[0049] The cross-sectional shape of the second engagement portions 63-66 is not limited to the U-shaped shape as in the above embodiment, and may have other cross-sectional shapes. For example, the second engagement portions 63-66 may have a T-shaped or semicircular cross-sectional shape.

[0050] Fig. 15 is a perspective view showing the cover 3 of the electromagnetic relay 1 according to the first modified example. As shown in Fig. 15, the cover 3 may include reinforcing ribs 71-73 connected to the cover main body 60. In this case, the rigidity of the cover 3 is improved, making it even more difficult for the second engaging portions 63-66 to come off the second engaged portions 42-45.

[0051] Fig. 16 is a front view showing an electromagnetic relay 1 according to a second modified example. As shown in Fig. 16, magnets 74, 75 for arc control may be arranged inside the case 2. For example, the magnets 74, 75 may be arranged in the first internal space S2 of the upper case 7. Alternatively, the magnets 74, 75 may be arranged in the second internal space S3 of the lower case 8 and the inner board 9. The magnets 74, 75 may be arranged so that the arc extends in a direction different from the pressure release path from the contact portion 6 toward the first main opening 12. This prevents the arc from leaking outside the case 2 when the cover 3 is in the pressure release position.

[0052] Fig. 17 is a perspective view showing an electromagnetic relay 1 according to a third modified example. As shown in Fig. 17, the case 2 may further include second sub-openings 76, 77 in addition to the sub-openings 48-51 (first sub-openings) described above. The second sub-openings 76, 77 may be provided on the left side surface 16 on the long side. Although not shown, a second sub-opening may also be provided on the right side surface 17, similar to the second sub-openings 76, 77. In this case, the pressure relief performance of the electromagnetic relay 1 is further improved.

[0053] Fig. 18 is a perspective view showing an electromagnetic relay 1 according to a fourth modified example. As shown in Fig. 18, the cover 3 may include a gap cover portion 78. The gap cover portion 78 may be arranged to close the gap between the cover main body 60 and the case 2 when the cover 3 is in the pressure release position. In this case, the direction in which the arc, molten metal, or the like leaks from the case 2 can be controlled.

[0054] Fig. 19 is a perspective view showing an electromagnetic relay 1 according to a fifth modification. As shown in Fig. 19, an outer cover 79 may be provided to cover the electromagnetic relay 1. The outer cover 79 may be arranged to cover at least the gap between the cover 3 and the case 2 when the cover 3 is in the pressure release position. This improves protection of the peripheral circuits of the electromagnetic relay 1 during pressure release.

[0055] In the above embodiment, the first main opening 12 is opened by the cover 3 moving upward in parallel with the case 2. However, the manner of movement of the cover 3 is not limited to that in the above embodiment and may be changed.

[0056] For example, Fig. 20 is a perspective view showing an electromagnetic relay 1 according to a sixth modified example. As shown in Fig. 20, the case 2 may include a hinge 80. The cover 3 may be rotatably supported by the hinge 80. In this case, the direction in which air leaks to the outside when pressure is released can be easily controlled.

[0057] The cover 3 is not limited to a single-swing type as in the sixth modified example shown in Fig. 20, but may be a double-swing type. Fig. 21 is a perspective view showing an electromagnetic relay 1 according to a seventh modified example. As shown in Fig. 21, the cover 3 may include a first cover portion 3A and a second cover portion 3B that are separate from each other. The first cover portion 3A and the second cover portion 3B may be rotatable about hinges 80 independently of each other.

[0058] Fig. 22 is a perspective view showing an electromagnetic relay 1 according to an eighth modification. As shown in Fig. 22, the cover 3 may be moved laterally relative to the case 2 to move from the normal position to the pressure release position.

[0059] 23 and 24 are perspective views showing an electromagnetic relay 1 according to a ninth modification. As shown in Fig. 23 and 24, the upper case 7 may be held in either the normal position shown in Fig. 23 or the pressure release position shown in Fig. 24. In the normal position shown in Fig. 23, the cover 3 may close the first main opening 12, and the lower case 8 may close the second main opening 13. In the pressure release position shown in Fig. 24, the cover 3 may open the first main opening 12, and the lower case 8 may open the second main opening 13.

[0060] The upper case 7 may include third engaged portions 85, 86. The lower case 8 or the inner board 9 may include third engaging portions 87, 88. The above-mentioned mounting claws 19A, 19B may engage with the mounting holes 18A, 18B, thereby holding the upper case 7 in the normal position, as shown in FIG. 23. After the mounting claws 19A, 19B are disengaged from the mounting holes 18A, 18B due to an increase in internal pressure, the third engaging portions 87, 88 may engage with the third engaged portions 85, 86, thereby holding the upper case 7 in the pressure relief position, as shown in FIG. 24. In this case, the pressure relief performance of the electromagnetic relay 1 is further improved.

[0061] Fig. 25 is a side view showing an electromagnetic relay 1 according to a tenth modification. As shown in Fig. 25, a retaining plate 89 may be disposed above the cover 3 to prevent the cover 3 and the upper case 7 from being blown off.

[0062] Fig. 26 is a cross-sectional view of the cover 3 and case 2 of an electromagnetic relay 1 according to an eleventh modification. As shown in Fig. 26, the upper case 7 may include a guide 90. The guide 90 may be arranged to guide air that flows out from the gap between the cover 3 and the upper case 7 when the cover 3 is in the pressure relief position. In this case, the direction in which air leaks to the outside when pressure is relieved can be easily controlled.

[0063] Fig. 27 is a perspective view showing an electromagnetic relay 1 according to a twelfth modification. As shown in Fig. 27, the electromagnetic relay 1 may be covered by an outer cover 92 having an air vent 91. The air vent 91 may connect the space inside the outer cover 92 to the outside of the outer cover 92. In this case, the direction in which the arc, molten metal, or the like leaks from the case 2 can be controlled. [Industrial Applicability]

[0064] According to the present invention, in an electromagnetic relay, it is easy to adjust the rigidity of the engaging portion for preventing the cover from being blown off when an arc occurs. [Explanation of symbols]

[0065] 2: Case, 3: Cover, 6: Contact portion, 7: Upper case, 8: Lower case, 11: Side wall, 12: First main opening, 13: Second main opening, 14: Front surface, 15: Rear surface, 16: Left side surface, 17: Right side surface, 20: Partition wall, 29A: Fixed contact, 31A: Movable contact, S1: Internal space, 40: First engaged portion, 42: Second engaged portion, 48: Sub-opening (first sub-opening), 60: Cover body, 61: First engaging portion, 63: Second engaging portion, 67: Left edge, 68: Right edge, 69: Front edge, 70: Rear edge, 71: Reinforcing rib, 76: Second sub-opening, 78: Gap cover portion, 80: Hinge, 90: Guide

Claims

1. a contact portion including a fixed contact and a movable contact; a case including an internal space in which the contact portion is disposed, a sidewall surrounding the internal space, a first main opening that connects the internal space with the outside, a first engaged portion, and a second engaged portion; a cover attached to the case; Equipped with The cover is The cover body, a first engagement portion connected to the cover body; a second engaging portion connected to the cover body at a position different from that of the first engaging portion; Including, The cover is held in either a normal position in which the first engaging portion engages with the first engaged portion and the cover body closes the first main opening, or a pressure release position in which the second engaging portion engages with the second engaged portion and the cover body opens the first main opening. Electromagnetic relay.

2. The case includes a sub-opening disposed between the contact portion and the first main opening.

2. The electromagnetic relay according to claim 1.

3. When the cover is in the normal position, the second engagement portion closes the sub-opening, When the cover is in the pressure release position, the second engagement portion opens the sub-opening.

3. The electromagnetic relay according to claim 2.

4. a partition wall that separates the contact portion from the first main opening; 2. The electromagnetic relay according to claim 1.

5. the side wall includes a long side surface and a short side surface, the first engaged portion is provided on the surface of the long side, The second engaged portion is provided on the surface of the short side.

2. The electromagnetic relay according to claim 1.

6. The cover body includes a long side edge and a short side edge, The first engagement portion is connected to an edge of the long side, The second engagement portion is connected to an edge on the short side.

6. An electromagnetic relay according to claim 5.

7. The surface on the short side has an uneven shape.

6. An electromagnetic relay according to claim 5.

8. The case is a first sub-opening provided on the surface of the short side and disposed between the contact portion and the first main opening; a second sub-opening provided on the surface of the long side and disposed between the contact portion and the first main opening; Including, 6. An electromagnetic relay according to claim 5.

9. The cover includes a reinforcing rib connected to the cover body.

2. The electromagnetic relay according to claim 1.

10. The cover includes a gap cover portion that closes the gap between the cover body and the case when the cover is in the pressure release position.

2. The electromagnetic relay according to claim 1.

11. The cover moves upward relative to the case to move from the normal position to the pressure release position.

2. The electromagnetic relay according to claim 1.

12. The cover moves from the normal position to the pressure relief position by moving laterally relative to the case.

2. The electromagnetic relay according to claim 1.

13. the case includes a hinge; The cover is rotatably supported by the hinge.

2. The electromagnetic relay according to claim 1.

14. The case is The lower case and an upper case disposed above the lower case; Including, the first main opening is provided on the top surface of the upper case, the upper case includes a second main opening provided on a lower surface of the upper case, the upper case is held in either a normal position in which the lower case closes the second main opening or a pressure release position in which the lower case opens the second main opening; 2. The electromagnetic relay according to claim 1.

15. the case includes a guide that guides air flowing out from a gap between the cover and the case when the cover is in the pressure relief position.

2. The electromagnetic relay according to claim 1.

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